1. Field of the Invention
The present invention relates to an ultra-thin Mo--C film transistor utilizing the piezoelectric effect. More particularly, the invention relates to the novel structure of a transistor involving a piezoelectric film inserted between a gate electrode and an ultra-thin Mo--C film having a source and a drain electrodes at opposite ends thereof, wherein on electrical signal applied to a gate electrode modulates the current of the ultra-thin Mo--C film between the source and drain electrodes held at a constant voltage.
2. Description of Prior Art
A piezoelectric material has a linear relation between an electric field and a resulting mechanical stress/strain, and such materials have been utilized in a variety of piezoelectric devices. Most piezoelectric devices thus convert the mechanical stress/strain to an electrical signal, or vice versa. Insulators such as quartz, LiNbO.sub.3, BaTiO.sub.3, PbTiO.sub.3 and the like, and semiconductors such as ZnS, InSb, CdS and the like, are known to be piezoelectric.
The simplest stress/strain transducer places a piezoelectric body in contact with the sensing area of the mechanical stress/strain and measures the electric potential difference between both surfaces of the piezoelectric body. This simple device converts a mechanical signal into a electrical potential signal.
In a more advanced form of a stress/strain transducer, a semiconductor material, such as Si, Ge, or the like, can be coupled to the piezoelectric material. The semiconductor material converts the electrical field caused by the piezoelectric material into a change in the semiconductor channel charge, resulting in a current modulation in a constant voltage mode.
Another form of such device is to employ a piezoresistive material which changes its resistivity according to mechanical forces. Some forms of semiconductor material, if properly processed, are known to exhibit such a piezoresistive effect.
As described above, most devices using a piezoelectric material convert a mechanical signal, represented by a stress or strain, into a electrical signal in one form or other.
Most electronic devices are mainly comprised of semiconductors and are being developed to meet the demands of increased capacity, i.e., higher integration. However, the involved technologies have many problems related to the integration capacity of the semiconductor-based device elements, with respect to nanometer-scale processing technology and the parasitic effects originating from the quantum effect as the device element become smaller than 10 nm. One way to solve this problem is to devise a three dimensional integrated circuit and to develop the device element suited for this purpose. One scheme includes a laminated structure a plurality of layers, wherein one unit layer is composed of a planar integrated circuit with an insulating layer. This semiconductor-based device is difficult to fabricate because it requires significant crystallinity for each unit of the integrated circuit and the present technique of overgrowing a base semiconductor layer upon an insulator is insufficient to provide the required crystallinity.